Hey Phoenix, my DD has pretty sensitive skin (gets patchy eczema on her trunk) and we've never had a problem with microfleece liners. She did get rashes when I didn't use the liners though.
Miocrofleece is fairly inexpensive, so it could be worth giving it a go just to see?
I've heard raw silk is good for liners for babies prone to nappy rash. We never tried it and I wonder how effective it'd be at wicking away moisture... But that's another idea.